A bearing is a connector allowing connected members to rotate relative to each other. Often one of the members is fixed, and the bearing acts as a support for the rotating member. Bearings include rolling elements that may take many forms, but are principally classified as balls or rollers. The rollers may likewise take a variety of forms, which are principally uniform cylinders, barrels, or cones, depending upon the application.
A unique feature of rolling element bearings is that their useful life typically is not determined by wear, but rather by fatigue of the operating surfaces due to repeated stresses associated with use. It is generally accepted that fatigue failure of rolling element bearings occurs as a result of progressive flaking or pitting of the surfaces of the rolling elements and the surfaces of corresponding bearing races. This flaking and/or pitting causes the rolling elements to seize, thereby generating intense heat, pressure, and friction.
Typically, a bearing cup is installed in a bearing housing or mounting flange with an interference fit based on the design requirements.
However, the mounting flange is typically not designed to uniformly, elastically deform during installation of the bearing cup. For instance, when a bearing cup is press fit into the flange, regions having a high radial stiffness deform less than regions having a low radial stiffness. Accordingly, non-uniform strain is applied to the bearing cup when the cup is press fit into a mounting flange having an inconsistent shape. As such, the bearing cup is deformed to have localized radial protrusions. The protrusions are high points in the cup that the bearing rolling elements must roll over, which causes fatigue failure of the cup and rollers, resulting in damage to the bearings.
One attempt to address the deficiencies caused by non-uniform strain is disclosed in U.S. Pat. No. 3,692,372 to Pineo. Pineo discloses an outside bearing race fixed to an engine frame using an annular bearing support plate. The support plate includes an axially thickened boss portion, through which a lubricant aperture extends. Three cuts isolate three sides of the axially thickened boss from the remainder of the bearing support plate, thereby allowing uniform radial thermal expansion of the outer bearing race.
However, Pineo fails to address expansion of a flange having an uneven radial thickness, such as occurs when a mounting flange has ears for attachment to other components. Furthermore, Pineo does not address the non-uniform expansion that occurs during press fitting of a bearing cup into the mounting flange. Finally, Pineo fails to address the problems that occur when applied loads are not only axial, but also are radial.
The present application is directed at overcoming one or more of the deficiencies in the art.